Health professional resource.

Cardiovascular disease (CVD) is one of Australia’s biggest health problems, claiming a life every 12 minutes and accounting for one in four deaths (1). It remains one of the largest health burdens on our economy (2).

Many CVD risk factors (including abnormal blood lipids, high blood pressure and type 2 diabetes) are preventable through adherence to a healthy diet and lifestyle.

The impact of nut consumption on heart disease risk has been extensively investigated since the publication in 1992 of the Adventist Health Study, which linked regular nut consumption, for the first time, with a lower risk of coronary heart disease (3).

Since then, a wealth of consistent evidence has firmly established nuts as potent cardioprotective foods.

What does the research say?

Evidence from systematic reviews and meta-analyses shows that regular nut consumption reduces the risk of CVD by positively impacting many CVD biomarkers, and for those with CVD, reduces the risk of dying from it.

Australian researchers recently conducted a systematic review and meta-analysis of randomised controlled trial studies, to quantify the relationship between nut consumption and CVD (4).

The meta-analysis showed regularly eating a handful of nuts (30g), significantly reduced LDL cholesterol, total cholesterol (TC), triglycerides (TG), TC:HDL cholesterol, LDL:HDL cholesterol, and apolipoprotein B (apoB).

Another comprehensive study – an umbrella review of more than 145 systematic reviews and
meta-analyses – found nuts and seeds consumption to be linked with major health benefits (5).

Eating a handful (an ounce, or 28g) of nuts a day, compared to eating no nuts, was linked with:
• 25% reduced risk for CHD
• 22% reduce risk of death from CVD
• 22% reduced risk of dying from all causes
• 21% reduced risk for CVD

How do nuts support heart health?

• Nuts contain higher amounts of unsaturated fatty acids, relative to saturated fatty acids – and this is a well-established mechanism for improving total and LDL-cholesterol. Some nuts also contain n-3 polyunsaturated fatty acids, which may decrease triglyceride levels.

• Plant phytosterols, which are found in nuts, are associated with reductions in cholesterol levels. Phytosterols decrease cholesterol absorption and increase faecal cholesterol excretion.

• Nuts are the richest plant source of the amino acid L-arginine, which is involved in the synthesis of nitric oxide – a vasodilator, which improves endothelial function and helps regulate blood pressure.

• Nuts contain a range of antioxidant phytochemicals (such as polyphenols, vitamin E, riboflavin, selenium, manganese, copper and zinc) which can positively affect lipid oxidation, oxidative stress and platelet function.

• The fibre, and particularly soluble fibre, in nuts helps lowers cholesterol reabsorption by binding to cholesterol in the small intestine.